i have a small spot on my scalp where all of the hair is gone. it's hidden by the rest of my hair so i barely noticed it but fuck if it didn't freak me out.

oh no! it can happen under a lot of stress but it's worth asking your doctor about when you go next.

Talk to a dermatologist. Worse comes to worse, Rogaine is really effective

Oh gosh, that would be disconcerting. I'd talk to a doctor, especially if you're on any meds, since losing hair can be a weird side effect of some things.